Trimeprazine is an antihistamine used to reduce itching from allergies, hives, eczema, and other causes (such as insect bites, chickenpox, reactions to certain drugs). It may also be used to treat cough from various causes (such as throat irritation, asthma, allergy, hay fever). This medication works by blocking certain natural substances (histamine, acetylcholine) that your body makes. To reduce itching and cough, it may also act directly on certain parts of the brain.

This medication should not be used by children younger than 2 years due to an increased risk of side effects.

Take this medication by mouth as directed by your doctor, usually twice a day after meals and at bedtime. This medication may also sometimes be taken only at bedtime.

The dosage is based on your age, medical condition, and response to treatment. Do not increase your dose or take this medication more often without your doctor's approval. Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day.

Tell your doctor if your condition lasts or gets worse.

Drowsiness, dizziness, headache, stomach upset, blurred vision, decreased coordination, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If any of these effects last or get worse, contact your doctor or pharmacist promptly.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• face/muscle twitching
• mental/mood changes (such as hallucinations, depression, nervousness)
• shaking (tremors)
• trouble urinating
• uncontrolled movements
• easy bruising/bleeding
• fast/irregular heartbeat
• seizure

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or to phenothiazines (such as chlorpromazine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• blood disorders (such as bone marrow depression)
• breathing problems (such as asthma, emphysema)
• a certain eye problem (glaucoma)
• heart problems
• high blood pressure
• liver disease
• seizures
• stomach/intestinal problems (such as ulcers, blockage)
• overactive thyroid (hyperthyroidism)
• urination problems (such as trouble urinating due to enlarged prostate, urinary retention)

This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Children may be more sensitive to the side effects of this drug. This drug can often cause excitement in young children instead of drowsiness.

Older adults may be more sensitive to the side effects of this drug, especially dizziness, drowsiness, and low blood pressure.

During pregnancy, this drug should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or other antihistamines (such as cetirizine, diphenhydramine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

This medication may interfere with certain lab tests (such as allergy skin test), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include: large pupils, flushing, fever, hallucinations, weakness, shaking (tremors), muscle twitching, loss of consciousness, seizures. In children, excitement may occur first, and may be followed by loss of coordination, drowsiness, loss of consciousness, seizures.

Do not share this medication with others.

If you miss a dose, take it as soon as you remember. If it is near the time of your next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.